Folks, my best guess is that it was a turkey vulture, which are known to upchuck and poop when alarmed and in a vulnerable situation, like naked in the bathtub. I've videod vultures and other raptors at this pool in hot weather, so it seems possible the bird's ablutions were rudely interrupted by Fred's barking. Of course I can't prove it; so those of you who thought it was regurgitated meat were correct. Carrying the wrench is just one of my quirks.